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Highly transparent, conducting, highly oriented, and almost single phase ZnO films have been deposited by simple e-beam evaporation method, and the deposition parameters were optimized. The films were prepared by (a) evaporation of ZnO at different substrate temperatures and (b) evaporation of ZnO at room temperature and subsequent annealing of the films in oxygen ambient at different temperatures. The characterizations of the film were performed by optical absorption spectroscopy (UV-visible), Fourier transform infrared spectroscopy, resistivity measurement, transmission electron microscopy (TEM), photoluminescence, and x-ray diffraction measurement. Absorption spectra revealed that the films were highly transparent and the band gap of the pre- and postannealed films was in good agreement with the reported values. The band gap of the films increases on increasing the substrate temperature as well as annealing temperature, whereas the resistivity of the film decreases with substrate temperature and increases with annealing temperature. Fourier transform infrared spectroscopy of ZnO films confirms the presence of Zn–O bonding. X-ray diffraction, electron diffraction, and TEM images with high resolution and Raman spectra of the films showed the formation of crystalline ZnO having wurtzite structure

Iron-phthalocyanine molecules deposited on the Au(110) reconstructed channels assemble into one-dimensional molecular chains, whose spatial distribution evolves into different structural phases at increasing molecular density. The plasticity of the Au channels first induces an ordered phase with a 5×5 symmetry, followed by a second long-range ordered structure composed by denser chains with a 5×7 periodicity with respect to the bare Au surface, as observed in the low-energy electron-diffraction (LEED) and grazing incidence X-ray diffraction (GIXRD) patterns. The geometry of the FePc molecular assemblies in the Au nanorails is determined by scanning tunneling microscopy (STM). For the 5×7 phases, the GIXRD analysis identifies a "4-3" rows profile along the [001] direction in the Au surface and an on-top FePc adsorption site, further confirmed by density functional theory (DFT) calculations. The latter also reveals the electronic mixing of the interface states. The chain assembly is driven by the molecule-molecule interaction and the chains interact with the Au nanorails via the central metal atom, while the chain-chain distance in the different structural phases is primarily driven by the plasticity of the Au surface.

Fractal and multifractal characteristics of self-affine surfaces of BaF2 thin films, deposited on crystalline Si ⟨1 1 1⟩ substrate at room temperature, were studied. Self-affine surfaces were prepared by irradiation of 120 MeV Ag(9+) ions which modified the surface morphology at nanometer scale. The surface morphology of virgin thin film and those irradiated with different ion fluences are characterized by atomic force microscopy technique. The surface roughness (interface width) shows monotonic decrease with ion fluences, while the other parameters, such as lateral correlation length, roughness exponent, and fractal dimension, did not show either monotonic decrease or increase in nature. The self-affine nature of the films is further confirmed by autocorrelation function. The power spectral density of thin films surfaces exhibits inverse power law variation with spatial frequency, suggesting the existence of fractal component in surface morphology. The multifractal detrended fluctuation analysis based on the partition function approach is also performed on virgin and irradiated thin films. It is found that the partition function exhibits the power law behavior with the segment size. Moreover, it is also seen that the scaling exponents vary nonlinearly with the moment, thereby exhibiting the multifractal nature.

Fractal characterization of surface morphology can be useful as a tool for tailoring the wetting properties of solid surfaces. In this work, rippled surfaces of Si (100) are grown using 200 keV Ar+ ion beam irradiation at different ion doses. Relationship between fractal and wetting properties of these surfaces are explored. The height-height correlation function extracted from atomic force microscopic images, demonstrates an increase in roughness exponent with an increase in ion doses. A steep variation in contact angle values is found for low fractal dimensions. Roughness exponent and fractal dimensions are found correlated with the static water contact angle measurement. It is observed that after a crossover of the roughness exponent, the surface morphology has a rippled structure. Larger values of interface width indicate the larger ripples on the surface. The contact angle of water drops on such surfaces is observed to be lowest. Autocorrelation function is used for the measurement of ripple wavelength.